Jerking with CVT upon 40 mph and stopping

[zippeh]

I just bought a 2015 Mirage DE with about 24,500 miles on it. It was a used rental, but I got it for $6850, which was a good deal! I have searched these forums and found that some jerk coming to a stop with the Mirage may be normal. What I have noticed is that when I am accelerating, I feel the car jerk (as if the car changed gears) at about 40-45mph while keeping the rpm at ~2300. I know that the CVT is supposed to be buttery smooth, which it is when I accelerate at faster rpms. I have to get two recalls done on the vehicle, so I am going in on Saturday. I thought I would pick some of your brains and get some ideas of what may be going on so that the dealer doesn't brush off a problem with my new vehicle.

[Frank_A05]

I too bought my mirage as a used rental.... Through Hertz car sales. Seems like you got a really good deal!

From my experience, This particular CVT is not buttery smooth in the slightest. You may or may not have a problem depending on how severe of a jerk you have going on.

Also, the CVT doesn't really "change gears" it will change the gear ratio based on your throttle input and the conditions (Inclines, declines, traction, etc.). It will settle to a lower ratio as you reach your desired speed, based mainly on the amount of throttle input you are giving at the time.

Are you experiencing this as you reach 45mph, or while traveling along steadily at 45?

[zippeh]

I too bought my mirage as a used rental.... Through Hertz car sales. Seems like you got a really good deal!

From my experience, This particular CVT is not buttery smooth in the slightest. You may or may not have a problem depending on how severe of a jerk you have going on.

Also, the CVT doesn't really "change gears" it will change the gear ratio based on your throttle input and the conditions (Inclines, declines, traction, etc.). It will settle to a lower ratio as you reach your desired speed, based mainly on the amount of throttle input you are giving at the time.

Are you experiencing this as you reach 45mph, or while traveling along steadily at 45?

Thanks for your reply! Yeah, I too bought it from Hertz! Has some scatches here and there, but overall in great condition!

I totally understand that the CVT doesn't actually change gears. The best way to describe what is happening (or what I'm feeling) is "like" the car is changing gears. It does it when accelerating from stop to 40-45 while keeping the rpms at a steady 2,300 rpm. No change in gas pedal pressure, no change in incline. During this "shifting feeling", the rpms do not change (as expected). All I know is that this is not how the car should handle, at least from a CVT perspective.

[Eggman]

I think there might be a misunderstanding here. This CVT has a set of gears, essentially making it a dual-range unit. This gives it a very wide ratio, improving fuel economy.

Read through this post: Information about the Mirage CVT (Jatco CVT7 JF015E) operation, video, diagrams for details on this transmission. It's not really a new product - it's been in production since 2009, and is developed for handling more power than the Mirage's 3A92 develops.

My Mirage is a manual transmission, so I don't have experience with the CVT in these cars. From what I've read, it sounds like a clever bit of machinery.

[Cobrajet]

There is a two-speed automatic gearbox attached to the transmission in this car, so it is not a 'straight' CVT. I am sure that is what you are feeling.

As Eggman mentioned, this is done for the sake of low speed acceleration and high speed fuel economy.

[MightyMirageMpg]

To decipher between the transmission "shifting" between high and low, and an actual problem, couldn't the transmission be intentionally operated in "B" mode, instead of drive?

...I'm just thinking out loud here....

[inuvik]

To decipher between the transmission "shifting" between high and low, and an actual problem, couldn't the transmission be intentionally operated in "B" mode, instead of drive?

...I'm just thinking out loud here....

Well you could at low speeds but "B" is the much lower gear range than "D". Think of the CVT like an old GM Powerglide. 2 speed automatic but the difference beiing a range of ratios available in each gear. At 70 mph rpm's are over 4500 in "B".

[Eggman]

If the 'jerking' no longer occurred while operating in B, then it could indicate that the jerking would be caused by the transmission shifting from low range to high range - which, is normal.

I've often wondered how this CVT managed that transition. That is, while shifting from low range to high, it would also need a corresponding change in the pulleys & belt. That little juggling act could explain all this.